Reading comments in the B-29 thread about the cool advanced technologies developed towards the end of WW2, I thought someone might be interested in this program to use trained pigeons to guide missiles. It's from....

...and the rest of the site has fantastic info on a whole range of other technologies, many of them from WW2 as well.

In one of the odder stories of World War II, the US military backed an investigation into weapons guided by trained pigeons. The investigation was conducted by the well-known behavioral psychologist Burrhus Frederic Skinner.

In early 1942, Skinner, then of the University of Minnesota, conducted preliminary studies on the concept of using trained animals as a guidance system. The studies were funded at a low level by General Mills, a major food producer.

The US National Defense Research Committee (NDRC), which funded new technologies that might be useful for winning the war, was skeptical of the idea, but in mid-1943 awarded a $25,000 USD contract to General Mills to continue the work. The investigation was codenamed PROJECT PIGEON, and Skinner hoped to be able to use pigeons to guide a weapon to within 6 meters (20 feet) of a target.

Three pigeons were each tucked into a jacket made of a sock and then put into a harness inside the guidance system, facing a screen. An image of the target was projected onto each of the three screens through a lens system in the nose of the weapon, with crosshairs defined by beams of light. Each pigeon was supposed to peck at its screen, which was wired to provide feedback to the missile's flight controls, to keep the crosshairs on target. The system accepted inputs from all three pigeons, but only acted if two or all three agreed.

The pigeons were trained with slides of aerial photographs of the target, and if they kept the crosshairs on the target, they were rewarded by a grain deposited in a tray in front of them. Skinner later found that the pigeons were less easily disturbed under confusing circumstances if they were fed hemp (marijuana) seeds rather than grains.

Skinner hoped to fit the pigeon guidance system to a Pelican, but he never managed to overcome official skepticism. When he put on a demonstration in New Jersey of the pigeon guidance system for officials of the US Office of Scientific Research and Development (OSRD) he was bitterly frustrated to see they were amused rather than impressed.

PROJECT PIGEON was abandoned. Skinner went home with 24 trained pigeons, which he kept in a dovecote in his garden. Whether the idea was practical or not, it appears that Skinner as a academic psychologist simply was not on the same wavelength as the industrial engineers and military officials he was trying to work with, and never managed to communicate with them effectively.

These notes were taken from an interview with Skinner...

Where did you get the idea?
Late 1930s, the Nazis effectively used airplanes as offensive weapons
Spring of 1939, Skinner was on a train from Minneapolis to Chicago
Thinking idly about surface-to-air missiles as a possible means of defense
Thought infrared radiation from the exhaust of the engines seemed a possibility
Noticed a flock of birds flying alongside the train
Suddenly occurred to him: why not teach animals to guide missiles; pigeons
Research
1942, funded by General Mills
1943, US National Defense Research Committee (NDRC), awarded a $25,000 USD contract to General Mills to continue the work
Became classified project
3 pigeons were uniformed
In a jacket made of a sock
Put into a harness inside the bomb
Facing a screen
A lens system in the nose of the weapon projected 3 images (1 per pigeon)
Each screens had crosshairs defined by beams of light
Each pigeon pecked at its screen to keep the crosshairs on target
The pigeons were trained with slides of aerial photographs of the target
Rewarded if they kept the crosshairs on the target
Rewarded by a grain deposited in a tray in front of them.
Later Skinner used hemp seeds (marijuana) instead of grain (less distracted)
An automatic homing system; a pigeon-guided missile
To improve accuracy, 3-pigeon guidance system
Control of the bomb's was determined by majority rule
A lens in the nose of the bomb threw an image of the approaching target on a ground-glass screen
A pigeon trained to recognize the desired target pecked at it with its beak
If the target's image moved off center
the pigeon's pecking tilted the screen
which moved the bomb's tail surfaces
which corrected the bomb's course
Advantages
Accurate to within 20 feet of a target
Needed no materials in short supply
Difficult to jam
Simple build
Dedicated (one pigeon pecked 10,000 time in 45 minutes)
Reliable (when falling rapidly and with noise all around)
Cheap
Reaction
Skinner wanted to use his guidance system on a missile (Pelican)
Put on a demonstration in New Jersey
Officials of the US Office of Scientific Research and Development (OSRD) came
They were amused
PROJECT PIGEON was abandoned
Skinner went home with 24 trained pigeons (kept in dovecote in garden)
Army decided to go with RADAR

In modern terms this is a passive, trained neural network guidance system. A pigeon's brain is a much more powerful and robust neural network than any we can build today. Pigeons are also light and easy to "maintain". This guidance system can't be jammed and as it is passive, gives no warning from emissions such as radar. This is all an excellent combination.

All in all, a seemingly good idea that shouldn't have been dismissed so quickly.